In a suspension apparatus of a vehicle, for example, an upper link and a lower link are controlled to protrude or to retract by an actuator, thereby restraining variations in camber angle and tread of a wheel caused by bumping and rebounding in order to enhance steering stability performance (see, e.g., JP 6-047388 B2). The actuator includes a motor and a feed screw mechanism in which a male screw member is relatively rotated with respect to a female screw member by the motor.
In this type of actuator having a feed screw mechanism, a male screw member is rotatably supported by a housing through a ball bearing, a female screw member is supported by the housing via a slide bearing so as to be slidable in an axial direction thereof, and the male screw member is threadedly engaged with the female screw member. However, according to this configuration, movements of the male and female screw members in a radial direction are regulated so that, when an excessive load is applied between the male and female screw members in the radial direction load, a smooth actuation of the feed screw mechanism is obstructed.